Workers on an assembly line at a factory in Shaanxi Province, China, February 2020

Liu Xiao Xinhua / eyevine / Redux

The new coronavirus is shaping up to be an enormous stress test for globalization. As critical supply chains break down, and nations hoard medical supplies and rush to limit travel, the crisis is forcing a major reevaluation of the interconnected global economy. Not only has globalization allowed for the rapid spread of contagious disease but it has fostered deep interdependence between firms and nations that makes them more vulnerable to unexpected shocks. Now, firms and nations alike are discovering just how vulnerable they are.

But the lesson of the new coronavirus is not that globalization failed. The lesson is that globalization is fragile, despite or even because of its benefits. For decades, individual firms’ relentless efforts to eliminate redundancy generated unprecedented wealth. But these efforts also reduced the amount of unused resources—what economists refer to as “slack”—in the global economy as a whole. In normal times, firms often